Dispensing apparatus

ABSTRACT

A dispensing apparatus of the self-leveling type in which a vertically movable platform is balanced by a spring and in which a balance beam is interposed between the spring and the platform to permit adjustment for different types of materials carried on the platform. Among the features shown are adjustment of effective moments by moving the fulcrum while constraining the beam longitudinally; moving the fulcrum with gear, rack, and stationary track; moving the fulcrum by pivotal link; rolling of surfaces in the fulcrum region; constraining the beam by a pivotal link connected at a point spaced from the fulcrum; vertical arrangement of the beam and adjusting rod in a compact arrangement; and a multiple parallel support cord arrangement, together with other important related features.

ilniteda States Patent [1 1 Healy Mar. 27, 1973 [21] Appl. No.: 135,100

[52] US. Cl ..312/7l, 211/49 [51] Int. Cl ..A47f 1/00, B65g1/16 [58]Field ofSearch...312/7l, 319; 211/49; 221/226,

[56] References Cited UNITED STATES PATENTS 2,919,168 12/1959 Shivek..3l2/7l 2,896,790 7/1959 Bell et al.. ..211/49 2,769,568 11/1956 Eurey..220/93 3,302,827 2/1967 Marlow ..220/93 Primary Examiner-Casmir A.Nunberg AttorneyJohn Noel Williams [57] ABSTRACT A dispensing apparatusof the self-leveling type in which a vertically movable platform isbalanced by a spring and in which a balance beam is interposed betweenthe spring and the platform to permit adjustment for different types ofmaterials carried on the platform. Among the features shown areadjustment of effective moments by moving the fulcrum while constrainingthe beam longitudinally; moving the fulcrum with gear, rack, andstationary track; moving the fulcrum by pivotal link; rolling ofsurfaces in the fulcrum region; constraining the beam by a pivotal linkconnected at a point spaced from the fulcrum; vertical arrangement ofthe beam and adjusting rod in a compact arrangement; and a multipleparallel support cord arrangement, together with other important relatedfea- 38 Claims, 12 Drawing Figures Patented March 27, 1973 3,722,970

FIG I J r. Y"

Patented March 27, 1973 6 Sheets-Sheet 2 FIG Patented March 27, 19733,722,970

6 Sheets-Sheet 3 PEG 3 Patented March 27, 1973 3,722,970

6 Sheets-Sheet 4 Patented March 27, 1973 6 Sheets-Sheet 6 FIG DISPENSINGAPPARATUS In the dispensing of trays, glass, and cup racks, dishes,saucers, and the like in food service operation, it has been commonpractice to provide a table having a platform or elevator on which thearticles to be dispensed can be stacked. By properly balancing theplatform, the top of the stack of articles remains at a constant levelat all times. In the past, most of these platforms have been balanced bythe use of springs and, when the type of article to be dispensed ischanged, it has been necessary to change the type or number of springs.It has been suggested that the spring effect, hence the dynamic range,be regulated by use of a lever interposed between the spring and theelevator and by adjusting the effective moment arms, however this hasoccurred with various drawbacks.

It is an object of this invention to provide variable moment armself-leveling dispensers which are improved from the points of view ofwideness and ease of adjustability of dynamic range, simplicity, fewparts, ease of manufacture, compactness, and reliability of operationwithout maintenance. Particular objects are to provide a dispenser whichcan be simply adjusted by the operator from the top to readily vary thedynamic setting to permit self-level dispensing of such heavy articlesas oven ware or as light articles as paper tableware, and to do thiswith a dispensing apparatus having a simple and rugged mechanism whichis inexpensive to manufacture and which is capable of a long life ofuseful service with a minimum of maintenance.

This invention concerns a self-leveling dispenser comprising a frame, aplatform supported for vertical movement, an elongated balance beam forbalancing first and second loads applied to the beam at first and secondload points on opposite sides of a fulcrum, a spring providing the firstload and the platform providing the second load.

arms, and the beam is generally restrained against.

lengthwise movement during adjustment of the fulcrum.

In preferred embodiments of this aspect, the beam is generallyvertically arranged; the fulcrum is defined as a surface of revolution(e.g., a roller or a gear) along which the beam rolls slightly duringdispensing, and which rolls along the beam during adjustment ofposition; the adjustable fulcrum and beam provide a predetermined smallpivotal movement of the beam during movement of the fulcrum, thismovement being in a direction tending to change the force condition onthe spring in the sense opposite to the change due to movement of thefulcrum to provide a substantially constant support for the tare weightof the platform despite variation in the effective'spring rate obtainedby varying the, ratio of moment arms for the first and second loads.

In one embodiment of this aspect a follower, such as a sprocket, engagesa stationary track for movement along the direction of the track; thebeam engaging member, e.g., another sprocket, is secured for movementwith the track follower and for rotation with thefirst sprocket to causeadvancement along the beam.

In another embodiment of this aspect, the fulcrumdefining member iscarried by a link pivotally mounted on the frame and an axiallyadjustable linkage is connected to rotate the link to adjust the fulcrumalong the beam. Preferably the beam has a curved surface where engagedby the fulcrum-defining member, the curvature of this surface beingselected to maintain preselected tension conditions, avoid undue workduring adjustment while the link pivots, as well as to provide supportfor the tare weight of the platform as heretofore described.

In another aspect, the invention features connecting means forconnecting the platform and the spring to the beam constructed to applytheir respective loads from substantially fixed positions relative tothe frame, means defining a pivotal fulcrum for the beam, and means foradjusting the effective point of the fulcrum including restraining meanscomprising a freely pivotal elongated link mounted on the frame andsecured to the beam at a linking point spaced substantially from thefulcrum, the elongated link extending from the linking point in thegeneral direction of and past the fulcrum and positioning the beamlongitudinally relative to the aforesaid fixed positions.

In preferred embodiments of this aspect the distance along thiselongated link between the pivotal mounting of the link on the frame andthe linking point is greater than the distance along the beam betweenthese load points; the linking point is coincident with one of said loadpoints; and the elongated link extends generally along the elongatedaxis of the mid position of the beam and traverses an are less thanabout 30.

In still another aspect, the invention features a platform support meanscomprising a first elongated flexible element engaged with one end ofthe beam at the second load point, guide means including a guide memberfor flexible element mounted near the bottom of the frame, tie meansconnecting the elongated member at a point past the guide member to acluster of vertically oriented parallel elongated flexible members,separator means mounted on the frame near the top of the frame forreceiving the cluster of parallel elongated members from the tie meansand directing these members individually to selected spaced locations onthe platform, and means securing these members to the platform at thesespaced locations. In a preferred embodiment thereof, a multiple ,pulleyarrangement having a mechanical advantage greater than two is secured tothe beam at the second load point, the first elongated flexible elementpassing around the pulley arrangement between the second load point andthe guide member; and the cluster of elongated elements comprises threeflexible cables, with the separator means comprising a plurality ofsheaves mounted close to one another with their axes lying in a commonplane, and directing the three cables to spaced locations on theplatform located near the two opposite corners of one side of theplatform, and near the center of the opposite side of the platform.

In another aspect, the invention features adjusting means comprising anaxially adjustable elongated linkage external of the beam, this linkagehaving a line of action disposed generally along the length of the beam,one end of the linkage terminating at a permanently positioned rotaryknob mounted in an upper portion of the frame and accessible forrotation by an operator, and the other end being arranged to move alongthe beam to alter the position of one of the load points or of thefulcrum along the beam to vary the ratio of the moment arms of the beam.

In preferred embodiments: the adjustable linkage comprises a pair oftelescoping shafts threaded to each other, the upper shaft of this pairbeing connected through a universal joint to the knob, the lower end ofthe pair being connected to move the fulcrum means upon rotation of theknob; and the beam and the adjustable linkage both extend generally fromthe top of the dispenser downwardly. In another preferred embodiment theadjustable linkage is adapted to move one of the load points along thebeam and comprises a pivotal assembly including an axial lost motionconnection permitting axial lengthening and shortening of the linkageduring normal rotation of the beam during dispensing, without effectupon the setting of the adjustable linkage.

Other objects, features and advantages will appear to one skilled in theart from the following description of preferred embodiments of theinvention, taken together with the attached drawings thereof, in which:

FIG. 1 is a perspective view of a dispensing apparatus according to onepreferred embodiment of the invention;

FIG. 2 is a sectional view of the invention taken on,

the line IIII of FIG. 1, showing the platform in the up position;

FIG. 2a is a diagrammatic view corresponding generally to FIG. 2,showing the platform in the down position;

FIG. 3 is a horizontal sectional view of a' portion of the apparatustaken on the line IIIIlI of FIG. 2;

FIG. 4 is a view similar to FIG. 2 of another preferred embodiment, FIG.5 being a vertical side view and FIG. 6 a horizontal plan view of themechanism;

FIG. 7 is a diagrammatic view of the curved surface of the balance beamof FIGS. 4-6;

FIGS. 8, 9, and 10 are views similar to FIGS. 4, 5, and 6 of anotherpreferred embodiment; and,

FIG. 1 1 is a diagrammatic view of a platform support arrangementaccording to a preferred embodiment of the invention.

Referring first to FIG. 1, the dispensing apparatus, indicated generallyby the reference numeral 10, is shown'as having a generally cube-shapedenclosure 11 with an opening 12 at its upper surface. The enclosure maybe provided at the lower corners with casters 13. Along one side of theenclosure is a frame 14 on which is slidably mounted a platform 15supported on a pair of cantilever arms 15a. Resting on the platform arestacks of articles 16 which are to be dispensed by the operator 20. Inthe illustration, the articles 16 are shown as consisting of cups andsaucers. Located on the top of the frame 14 is an adjusting knob 17.

In FIGS. 2 and 3, it can be seen that cantilever arms 15a (one shown)for the platform 15 are provided with rollers 18 at the sides by whichit is guided on channel 51 in the frame 14 for vertical movement. Abalance beam 19 is mounted more or less centrally of the frame in agenerally vertical direction and is provided with a straight surface 21.Extending angularly from top to bottom of the frame are two stationaryparallel struts 22 and between these struts lies a slide 23 havingrollers 24 which engage and slide along the surface 21 of the beam 19.Hinged to the slide 23 by means of hinge pins 25 is a U-shaped bracket26 which is connected to the upper part of the frame by a downwardlyextending adjusting means, such as the screw 27 and a nut 28. The nut 28is fixed to an elongated tube 29 which is connected through a universaljoint 31 to the adjusting knob 17 mounted on the top of the apparatus.

Extending through the slide 23 is a shaft 32 on which are mounted threegears 33, 34 and 35 which engage racks 36, 37, and 38 attached to thesurfaces of the struts 22 and the beam 19. It can be seen that thisarrangement provides for a pivoting of the beam 19 about an axisdetermined by the inter-engagement of the gear 34 with the rack 37, thisbeing theoretically the intersection of the two pitch lines. Thus thefulcrum of the beam is defined by the gear.

At the upper end of the beam 19 is mounted a pulley 39 around whichextend cables 41, 41a leading to the platform 15. Cable 41a passesaround pulley 46 at the left, thence to pulley 44 at the right overwhich the cable passes as it goes to the right-hand side of the elevator15. Cable 41 passes over pulley 45 at the left, thence to the left-handside of the platform 15. Coil springs 47 are attached at one end to thetop of the frame, bracket 42, and at the other end to a cable 48. Thiscable passes around a pulley 49 rotatably mounted in the bottom of theframe 14 and is attached at its other end to the lower end of the beam19.

Referring to FIG. 3, it can be seen that the rollers 18, which guide theelevator 15, are operative on either side of a hollow tubular column 51,which is welded to the side of the frame 14.

For the operation of the invention the beam 19 should be visualized as afirst degree lever in which the contact of the gear 34 with the rack 37constitutes the fulcrum and in which two forces or loads are applied tothe ends of the lever or beam in opposite directions. One force isapplied at the lower end of the lever and is the force due to thestressing of the springs 47, while the other force operates on the upperend of the lever and represents the weight of the platform and itscontents as carried to the lever through the cables 41, 41a. The forcedue to the elevator 15 and its load is always applied to the extremeupper end of the lever and the force from the springs 47 is alwaysapplied to the lower end of the lever, but the fulcrum lies in theposition determined by the position of the slide 23 and the gear 34. Byadjusting the position of the slide 23 (and, therefore the position ofthe gear 34 on the lever) it is possi ble to adjust the effect of thespring 47 on the elevator to match various weights of articles carriedon the elevator. In other words, adjustment of the fulcrum leads toadjustment of the ratio of the spring moment arm to the load moment arm.The rotation of the nut 28 by means of the rotatable knob 17 will causethe nut to move to any of various positions along the screw 27. Thescrew is attached .to' the slide 23 in such a way that it can change itsangularity to compensate for the fact that the lengthening of the tube23 and the screw 27 causes them to heat a different angle to the beam19. When the nut 23 has been drawn close to the bracket 26, it has theeffect of moving the slide 23 closer to the upper end of the beam; thatis to say, closer to the pulley 39. This means that the spring 45 isoperating on a longer moment arm and is capable of balancing a largerforce on the elevator. It is only necessary for the attendant at thedispensing apparatus to turn the knob 17 after a complete load of dishesor new types of articles have been placed on the elevator. She turns theknob until the top of the stack appears at the opening 12 and, as sheremoves articles from the stack, the forces will cause the next lowerarticle to move up to the opening, so that there is always an articlelocated at a desired height above the opening 12 ready to be used.

This embodiment enables continual compensation for the tare weight ofthe platform. It will be understood that the tare weight is a fixedvalve, regardless of what kind of load is on the platform. When thefulcrum is moved to decrease the spring moment arm, according to theinvention an oppositely compensating effect on the spring is alsoapplied, so that at the light load setting a sufficient force remainsapplied to raise the elevator when empty. Referring to FIG. 2 it will beseen that in the up position the lower portion of surface 21 tends tomove past the angled strut. It will be seen therefore, that when thefulcrum is moved downward and to the left, when turning the knob to alower load setting as the sprockets 33 and 35 move down the strut, therollers 24 force the lower portion of the beam (which protrudes to theleft of the strut) to the right, adding tension to the spring, and thuscompensating for the tare weight of the platform.

In summary, it can be seen that this embodiment has a relatively simpleconstruction which can be adapted to use with a complete line ofdispensers, irrespective of the nature of the platform or elevator, thenature of the enclosure, or of the articles being dispensed. There isusually no necessity for changing springs because the nature of thespring action can be changed without difficulty to match the type ofarticles being dispensed. It is possible, however, by removing one ofthe springs 47 to arrange the machine to handle an entirely differentrange of weights of articles. The adjustment, however, once the springshave been changed, can be done without the need for a skilled mechanic.The apparatus is of such a nature that it can be built in a very ruggedmanner, so that its life will be extremely long and there will be noneed for maintenance.

FIGS. 4 to 7 show a self-leveling dispenser 100 having a frame 1 14 onwhich is mounted for vertical movement a platform for carrying a seriesof articles such as previously shown in FIG. 1. The platform is secured,by cable 118, through a pulley and cable system shown in detail in FIG.11, described below, to a block and tackle arrangement 120, whichincludes two coaxial sheaves 122, 124 mounted on the upper end ofbalance beam 126. The end of cable 118 is secured to the frame at 128,and the cable 118 passes successively over beam-mounted sheave 122, asheave 130 mounted on frame 114, beam-mounted sheave 124, a sheave 132mounted on frame 114 coaxially with sheave 130, and thence down alongframe 1 14 to lower sheave 134. The lower end of balance beam 126 isattached to cable 136, which passes around a sheave 138 rotatablymounted on a bracket 140 secured to frame 114, and is attached at itsother end to coil springs 47. A bracket 142 is secured to frame 114, andthe coil springs 47 are mounted on bracket 142.

Balance beam 126 has a curved surface 144 which is engaged by a rotarybearing 146 mounted on the free end of a U-shaped pivotal link 148,which is pivotally mounted at its other end by bracket 150 on frame 114.The curvature of surface 144 differs from the are 152 which is traversedby pivot link 148 about bracket 150, for purposes hereinafter described.An axially expansible member 154 includes telescoping, threadablyengaged shafts 156, 158 of which shaft 156 is rotatably mounted throughpin 160 to pivot link 148, and shaft 158 is secured through universaljoint 162 and shaft 164 to an exposed rotatable knob 166, such thatrotation of knob 166 rotates shaft 158 relative to shaft 156, expandingor contracting the axially expansible member 154.

Two elongated links 170, 172 commonly pivotally mounted at one end onframe 114 by bracket 174 and mounting pin 176, are connected at theirother ends to the upper end of balance beam 126 through mounting pin 178coaxially with beam-mounted sheaves 122,

Referring now to FIG. 11, the cable 118 travels from lower sheave 134around guide sheave 180, and is connected to tie structure 182.

Vertical cables 184, 186, 188 are secured at their ends to tie structure182. A three-sheave separator structure is mounted on frame 114 and hasthree vertical sheaves 192, 194, 196, mounted close together with theiraxes arranged in a single horizontal plane, and receive cables 184, 186,188, respectively. The end of cable 184 is secured to platform 115 atabout the midpoint 198 of one side of the platform. Cables 186 and 188travel to horizontal corner sheaves 202, 204, respectively, and thenceto vertical corner sheaves 206, 208 respectively. The ends of cables 186and 188 are secured to the corners 210, 212, respectively, of platform115. Since the three cables 184, 186, 188 are all connected to a singlevertically movable tie structure 182, the cables will move synchronouslyover the various sheaves, thereby maintaining platform 115 horizontal atall times.

In operation, when the load of platform 115 is increased by placingdishes or other articles on the platform, a pull is exerted throughcable 118 on balance beam 126, tending to pivot the beam about thefulcrum defined at the point of engagement of the rotary bearing 146carried by pivotal link 148, with the curved surface 144 of beam 126. Asthe beam pivots on its fulcrum, the cable 136 exerts a pull on coilsprings 47, increasing the spring force until it is sufficient to againbalance the load of platform 115, ceasing pivotal move ment of the beam.

The pivotal movement of the upper end of the beam is confined by links170, 172 to the arc traversed by those links. As seen in FIG. 4, thelinks 170, 172 are pivotally mounted at bracket 174 at about themidpoint of the arc traversed by the lower end of the beam duringpivotal movement of the beam. Since the arc traversed by the links 170,172 is flatter than the are that would otherwise be traversed by theupper end of the beam 126 about a fixed fulcrum located at the point ofengagement of rotary bearing 146 and curved surface 144, this point ofengagement will shift somewhat along the curved surface during pivotalmovement of the arc. The mounting of the links 170, 172 as described atthe midpoint of the range of travel of the beam and the flat arctraversed by the long elongated links result in very little verticalmovement of the ends of the beam during pivotal movement of the beam.Thus, the line of action along cables 118 and 136 between the beam andplatform 115 and springs 47 respectively remains substantiallyperpendicular throughout movement of the beam. Hence, the incrementalmovement of platform 115 in response to an incremental load change willremain about the same, regardless whether the platform has no dishesthereon, so that the tie structure 182 is near lower guide sheave andthe beam is at the full-line position shown in FIG. 4, or is fullyloaded, so that the tie structure 182 is near the three-sheave separatorstructure 190.

To adjust the response of the platform to the application of articles ofdifferent weight, the rotary bearing 146 is moved along the curvedsurface 144 of beam 126, thereby changing the fulcrum point of the beam.To adjust for lighter weights, the fulcrum point is moved toward thelower end of the beam, lengthening the platform moment arm relative tothe spring moment arm. To adjust for heavier weights, the fulcrum pointis moved toward the upper end of the beam.

Fulcrum adjustment is carried out by rotating adjusting knob 166 whichin turn either expands or contracts expansible member 154, therebypivoting pivotal link 148 about bracket 150. The links 170, 172 restrainthe balance beam 126 against longitudinal or vertical movement duringfulcrum adjustment. The curvature of beam surface 144 is selected notonly to compensate for the arcuate movement of the rotary bearing 146due to its being mounted in a pivotal link, thus maintainingsubstantially constant tension conditions and avoidance of performingwork during adjustment and also to compensate for the tare weight of theplatform. In particular, FIG. 7 shows that the curvature of surface 144deviates from the arc traversed by the pivotal link 148 in such a way asto cause balance beam 126 to pivot in a manner tending to adjust thespring force of coil springs 47 so as to compensate for the change inthe relative lengths of the platform moment arm and the spring momentarm. Thus, e.g., as the fulcrum is moved downwardly along the balancebeam, toward the lower end of the beam, increasing the platform momentarm, the lower end of the beam is caused to pivot toward the right, thuscausing cable 136 to expand coil springs 47.

FIGS. 8 to 10 show a self-leveling dispenser 250 having a frame 252, avertically movable elevator platform, and a generally verticallydisposed elongated balance beam 256 pivotally mounted on a pivot pin 258extending through the two sides 260, of the lower'V-shaped portion ofbalance beam 256, and journalled in a bracket 262 mounted on frame 252.Pivot pin 258 thereby defines a fixed fulcrum for the balance beam. Theupper end of balance beam 256 is secured through a block and tacklearrangement identical to that described above with reference to thedispenser 100 of FIGS. 4 to 7, to a cable 118 which is in turn securedto the platform through a pully arrangement also identical to thatdescribed with reference to dispenser 100. The lower end of balance beam256 terminates in a mounting block 263, through which is slidablyreceived the free end of an adjusting shaft 264, which is threadedadjacent block 263. Spring load nut 266 is threadedly engaged with shaft264, and is linked at each side to cable mount 268, and rollers 269,arranged to roll along the sides 260, 262, respectively, of balance beam256. One end of cable 270 is secured within cable mount 268, from whencethe cable 270 passes across guide sheave 272 and is connected at itsother end to coil springs 47. A guide block 276 mounted on balance beam256 has an internal bearing surface for the unthreaded portion ofadjusting shaft 264 received therein. A universal joint 278 pivotallyconnects the upper end of shaft 264 to a lost motion device 280consisting of an inner shaft 282 slidably received within an outerhollow shaft 284, the shafts 282, 284 being keyed by key 286 againstrelative rotation. Another universal joint 288 connects shaft 284 to theadjustable knob 290, which is otherwise identical to the adjustable knob17 shown and described with reference to FIGS. 1 and 4.

Adjustment of this dispenser for articles of different weight isachieved by rotating the shaft 264 by rotating knob 290, thus causingspring load nut 266 to move along shaft 264 relative to mounting block263, thus changing the position along said beam at which the coil springacts on the lever i.e., changing the length of the moment arm along thebalance beam from the fulcrum to the spring load. The spring load nut ismoved toward the fulcrum for lighter articles and away from, the ful-.crum for heavier articles.-

In operation, changing the load on the platform causes the balance beamto pivot on fulcrum pin 258, carrying threaded shaft 264 with it. As theshaft rotates with the balance beam, the shafts 282, 284 of the lostmotion device 280 slide axially with respect to one another toaccommodate the shortening or lengthening of the distance between theend of shaft 264 in mounting block 263 and the universal joint 288 atknob 290.

Other embodiments will be apparent to those skilled in the art and arewithin the following claims.

What is claimed is:

1. A self-leveling dispenser comprising a frame,

a platform supported for vertical movement,

an elongated balance beam for balancing a first load and a second-loadapplied to said beam at first and second fixed load points,respectively, spaced along said beam on opposite sides of a fulcrum,

a spring connected at one end to said frame and at the other end to saidbeam at the first load point to provide said first load,

means connecting said platform to said beam at the second load point toprovide said second load, and

fulcrum means including a beam-engaging member defining said fulcrum forsaid beam and adjusting means for moving said fulcrum-defining structurealong said beam to vary the distance along said beam between saidfulcrum and said load points,

and means for generally restraining said beam against lengthwisemovement during adjustment of said fulcrum.

2. The self-leveling dispenser of claim 1 wherein said fulcrum-definingstructure comprises a surface along which said beam rolls slightlyduring dispensing, and said adjusting means is adapted to shift theposition of said surface relative to the length of said beam.

3. The self-leveling dispenser of claim 2 wherein said surface is of thegeneral form of a surface of revolution,

- and said adjustment means is adapted to cause said surface to rollalong the length of said beam during adjustment.

4. The self-leveling dispenser of claim 3 wherein said surface ofrevolution is in the form of a gear, and a track therefor is provided onsaid beam.

5. The self-leveling dispenser of claim 3 wherein said surface is in theform of a roller mounted on a movable carrier.

6. The self-leveling dispenser of claim 1 wherein said beam is generallyvertically arranged and said adjusting means comprises a threaded shaftforming an elongated axially expansible linkage pivotally mounted onsaid frame separate from said balance beam, with the line of action ofsaid linkage disposed generally vertically, connected at its top to amanually rotatable knob, said linkage being expansible and contractibleto move said fulcrum-defining structure along said generally verticalbeam.

7. The self-leveling dispenser of claim 1 wherein said adjustablefulcrum means includes a stationary track, and track follower meansconnected to said adjusting means and engaging said track for movementalong the direction of said track, said beam engaging member beingsecured for movement with said track follower means, and arranged tomovingly contact said beam throughout said movement.

8. The self-leveling dispenser of claim 7 wherein said stationary trackcomprises a stationary rack, said track follower means comprises a firstrotatable sprocket engaging said rack, said balance beam has a racksecured along one elongated side of said beam, and said beamengagingmember comprises a second rotatable sprocket, and said apparatusincludes a sprocket mounting, commonly mounting said first and secondsprockets.

9. The self-leveling dispenser of claim 7 wherein said adjusting meanscomprises an axially expansible elongated linkage pivotally mounted onsaid frame and secured to said sprocket mounting, the line of action ofsaid expansible linkage being arranged generally parallel to saidtracks.

10. The self-leveling dispenser of claim 7 wherein said track comprisesfirst and second stationary parallel racks spaced from said beam withone rack extending along each side of said beam and said track followermeans comprises first and second coaxially mounted rotatable sprocketsarranged to engage said first and second racks, respectively.

11. The self-leveling dispenser of claim 10 wherein said beam includes athird rack mounted on said beam along the elongated direction of saidbeam, and said beam-engaging member comprises a third rotatablesprocket, coaxially mounted to turn with said first and secondsprockets, arranged to engage said third rack and providing said fulcrumat the point of engagement of said third rack and said third sprocket.

12. The self-leveling dispenser of claim 10 wherein said apparatusincludes a sprocket mounting, coaxially mounting the three sprockets,and restraining means mounted on said sprocket mounting for movementtherewith along said beam and arranged to contact the side of said beamopposite the side of said beam in which said third chain is mounted.

13. The self-leveling dispenser of claim 12 wherein said restrainingmeans comprises rollers engaging said opposite side of said beam.

14. The self-leveling dispenser of claim 1 wherein said adjustablefulcrum means and said beam are cooperatively mounted to provide apredetermined small pivotal movement of said beam during movement ofsaid fulcrum defining structure, said pivotal movement being in adirection tending to change the force condition on said spring in thesense opposite to the change due to movement of said fulcrum-definingstructure thereby to provide a substantially constant support for thetare weight of the platform despite variation in the effective springrate obtained by varying the ratio of moment arms for said first andsecond loads.

15. The self-leveling dispenser of claim 14 wherein said fulcrum iscarried on a stationary track, and said track is angled to cause saidchange in force condition during the adjusting movement of said fulcrumalong said track and beam.

16. The self-leveling dispenser of claim 1 wherein said fulcrum-definingstructure comprises a beam-engaging member carried by a link pivotallymounted on said frame, said fulcrum defined at the point of engagementbetween said beam and said beam-engaging member, and

said adjusting means comprises an axially adjustable linkage connectedto rotate said link thereby moving said beamengaging member along saidbeam to change the position of said fulcrum.

17. The self-leveling dispenser of claim 16 wherein said beam has acurved surface where engaged by said beam-engaging member, the curvatureof said surface being selected to maintain preselected tensionconditions between said arm and said beam as said beam-engaging membertravels over said curved surface in the arc defined by said pivotallink.

18. The self-leveling dispenser of claim 17 wherein the curvature ofsaid curved surface is selected to change the force condition on saidspring in the sense opposite to the changes due to movement of saidfulcrum to provide support for the tare weight of the platform despitevariation in the effective spring rate obtained by varying the ratio ofmoment arms for said first and second loads.

19. The self-leveling dispenser of claim 16 wherein a portion of saidbeam spaced from the area of said fulcrum means is pivotally connectedto an elongated link, said elongated link extending generally in thesame direction as said beam and pivotally mounted on said frame.

20. A self-leveling dispenser comprising a frame,

a platform supported for vertical movement,

an elongated balance beam for balancing a first load and a second loadapplied to said beam at first and second load points, respectively,spaced along said beam on opposite sides of a fulcrum,

a spring including first connecting means, said spring connecting at oneend to said frame and at the other end to said beam at the first loadpoint to provide said first load,

second connecting means connecting said platform to said beam at thesecond load point to provide said second load, said connecting meansconstructed to apply their respective loads from substantially fixedpositions relative to said frame, means defining a pivotal fulcrum forsaid beam,

and means for adjusting the effective point of said fulcrum along thelength of said beam and restraining means for generally restraining thebeam against lengthwise movement during adjustment of the fulcrum, saidrestraining means comprising a freely pivotal elongated link mounted onsaid frame and secured to said beam at a linking point spacedsubstantially from said fulcrum, said elongated link extending from saidlinking point in the general direction of and past said fulcrum, saidlink positioning said beam longitudinally relative to said fixedpositions.

21. The self-leveling dispenser apparatus of claim wherein the distancealong said linking member between the pivotal mounting of said link onsaid frame and said linking point is greater than the distance alongsaid beam between said load points.

22. The dispenser of claim 20 wherein said linking point is coincidentwith one of said load points.

23. The dispenser of claim 22 wherein said beam is coupled to therespective load at said coincident load point, by a sheave supporting anelongated flexible member connected to said load, the axis of saidsheave being located at said coincident load point, said beam and saidelongated links being connected at said linking point by a connectingpin coaxial with said sheave.

24. The self-leveling dispenser of claim 23 wherein said elongated linktraverses an are less than about 30.

25. The dispensing apparatus of claim 20 wherein said elongated linkextends generally along the elongated axis of the mid position of saidbeam.

26. A self-leveling dispenser comprising a frame,

a generally vertically arranged elongated balance beam for balancing afirst load and a second load applied to said beam at first and secondload points, respectively, spaced along said beam,

fulcrum means engaging said beam intermediate of said load pointsdefining a fulcrum for said beam,

a spring effectively connected at one end to said frame and at the otherend to said beam to provide said first load,

a vertically movable platform providing said second load, and

platform support means comprising a first elongated flexible elementengaged with one end of said beam at said second load point, guide meansincluding a guide member for said flexible element mounted near thebottom of said frame, tie means connecting said elongated member at apoint past said guide member to a cluster of at least three verticallyoriented parallel elongated flexible members, separator means mounted onsaid frame near the top of said frame for receiving said cluster ofparallel elongated members from said tie means and directing saidmembers individually to selected spaced locations on said platform, andmeans securing said members to said platform at said spaced locations.

27. The self-leveling dispenser of claim 26 including a multiple pulleyarrangement having a mechanical advantage greater than two secured tosaid beam at said second load point, said first elongated flexibleelement passing around said pulley arrangement between said second loadpoint and said guide member.

28. The dispenser of claim 26 wherein said cluster of elongated elementsare flexible cables, and said separator means comprises a plurality ofsheaves mounted close to one another with their axes lying in a commonplane.

29. The self-leveling dispenser of claim 28 wherein there are threecables in said cluster, and said spaced locations on said platform arelocated near the two opposite corners of one side of said platform, andnear the center of the opposite side of said platform.

30. A self-leveling dispenser comprising a frame a platform supportedfor vertical movement a generally vertically arranged elongated balancebeam for balancing a first load and a second load applied to said beamat first and second load points, respectively, on said beam fulcrummeans engaging said beam at a third point intermediate of the loadpoints defining a fulcrum for said beam,

a spring connected at one end to said frame and at the other end to saidbeam at the first load point to provide said first load,

means connecting said platform to said beam at the second load point toprovide said second load, and

adjusting means for varying the ratio of the first moment arm of saidbeam defined between said fulcrum and said first load point to thesecond moment arm of said beam defined between said fulcrum and saidsecond load point, said adjusting means comprising an axially adjustableelongated linkage external of said beam, said linkage having a line ofaction disposed generally along the length of said beam, one end of saidlinkage terminating at a permanently positioned rotary knob mounted inan upper portion of the frame and accessible for rotation by anoperator, the other end being arranged to move along said beam to alterthe position of one of said three points along said beam to vary saidratio.

31. The self-leveling dispenser of claim 30 wherein the movable end ofsaid axially adjustable linkage is connected to move the point of actionof said fulcrum means, and said adjustable linkage is stationary duringvertical movement of the platform.

32. The self-leveling dispenser of claim 31 wherein said fulcrum meanscomprises a beam-engaging member carried by a link pivoted to saidframe, said movable end of said adjustable linkage connected to movesaid link to a preselected position, said beam being constrained wherebythe point of action of said fulcrum means is adjusted along said beam bysaid movement of said link.

33. The self-leveling dispenser of claim 32 wherein a portion of saidbeam spaced from the area of said fulcrum means is pivotally connectedto an elongated link, said link extending generally parallel to saidbeam and pivotally mounted on said frame.

34. The selfleveling dispenser of claim 31' wherein said fulcrum meanscomprises a beam-engaging member carried along stationary guides.

35. The self-leveling dispenser of claim 31 wherein said adjustablelinkage comprises a pair of telescoping shafts threaded to each other,the upper shaft of said pair connected through a universal joint to saidknob, the lower end of said pair connected to move said fulcrum meansupon rotation of said knob.

36. The self-leveling dispenser of claim 30 wherein said first loadpoint for said spring is at the lower end of said moment arm and saidadjustable linkage is longer than said moment arm, extending from thetop of said dispenser downwardly to the lower end of said beam, saidlinkage adapted to shift said first load point along the length of saidbeam.

37. The self-leveling dispenser of claim 30 wherein said adjustablelinkage is adapted to move either said first or second load point alongsaid beam, said linkage comprising a pivotal assembly including an axiallost motion connection permitting axial lengthening and shortening ofsaid linkage during normal rotation of said beam during dispensing, saidlost motion connection permitting free movement of said beam withoutaffect upon the setting of said adjustable linkage.

38. The self-leveling dispenser of claim 37 wherein said linkagecomprises a pair of shafts telescopically fitted together and freelymovable axially relative to each other to define said lost motionconnection, said shafts being connected together for mutual rotation,the upper shaft of said pair connected through a universal joint to saidrotatable knob, the lower shaft connected through a universal joint to athreaded lead screw mounted on said beam, and a nut constrained inguides of said beam, said nut providing the connection for said load,the nut being threaded on said screw and driven therealong by rotationof said screw.

1. A self-leveling dispenser comprising a frame, a platform supported for vertical movement, an elongated balance beam for balancing a first load and a second load applied to said beam at first and second fixed load points, respectively, spaced along said beam on opposite sides of a fulcrum, a spring connected at one end to said frame and at the other end to said beam at the first load point to provide said first load, means connecting said platform to said beam at the second load point to provide said second load, and fulcrum means including a beam-engaging member defining said fulcrum for said beam and adjusting means for moving said fulcrum-defining structure along said beam to vary the distance along said beam between said fulcrum and said load points, and means for generally restraining said beam against lengthwise movement during adjustment of said fulcrum.
 2. The self-leveling dispenser of claim 1 wherein said fulcrum-defining structure comprises a surface along which said beam rolls slightly during dispensing, and said adjusting means is adapteD to shift the position of said surface relative to the length of said beam.
 3. The self-leveling dispenser of claim 2 wherein said surface is of the general form of a surface of revolution, and said adjustment means is adapted to cause said surface to roll along the length of said beam during adjustment.
 4. The self-leveling dispenser of claim 3 wherein said surface of revolution is in the form of a gear, and a track therefor is provided on said beam.
 5. The self-leveling dispenser of claim 3 wherein said surface is in the form of a roller mounted on a movable carrier.
 6. The self-leveling dispenser of claim 1 wherein said beam is generally vertically arranged and said adjusting means comprises a threaded shaft forming an elongated axially expansible linkage pivotally mounted on said frame separate from said balance beam, with the line of action of said linkage disposed generally vertically, connected at its top to a manually rotatable knob, said linkage being expansible and contractible to move said fulcrum-defining structure along said generally vertical beam.
 7. The self-leveling dispenser of claim 1 wherein said adjustable fulcrum means includes a stationary track, and track follower means connected to said adjusting means and engaging said track for movement along the direction of said track, said beam engaging member being secured for movement with said track follower means, and arranged to movingly contact said beam throughout said movement.
 8. The self-leveling dispenser of claim 7 wherein said stationary track comprises a stationary rack, said track follower means comprises a first rotatable sprocket engaging said rack, said balance beam has a rack secured along one elongated side of said beam, and said beam-engaging member comprises a second rotatable sprocket, and said apparatus includes a sprocket mounting, commonly mounting said first and second sprockets.
 9. The self-leveling dispenser of claim 7 wherein said adjusting means comprises an axially expansible elongated linkage pivotally mounted on said frame and secured to said sprocket mounting, the line of action of said expansible linkage being arranged generally parallel to said tracks.
 10. The self-leveling dispenser of claim 7 wherein said track comprises first and second stationary parallel racks spaced from said beam with one rack extending along each side of said beam and said track follower means comprises first and second coaxially mounted rotatable sprockets arranged to engage said first and second racks, respectively.
 11. The self-leveling dispenser of claim 10 wherein said beam includes a third rack mounted on said beam along the elongated direction of said beam, and said beam-engaging member comprises a third rotatable sprocket, coaxially mounted to turn with said first and second sprockets, arranged to engage said third rack and providing said fulcrum at the point of engagement of said third rack and said third sprocket.
 12. The self-leveling dispenser of claim 10 wherein said apparatus includes a sprocket mounting, coaxially mounting the three sprockets, and restraining means mounted on said sprocket mounting for movement therewith along said beam and arranged to contact the side of said beam opposite the side of said beam in which said third chain is mounted.
 13. The self-leveling dispenser of claim 12 wherein said restraining means comprises rollers engaging said opposite side of said beam.
 14. The self-leveling dispenser of claim 1 wherein said adjustable fulcrum means and said beam are cooperatively mounted to provide a predetermined small pivotal movement of said beam during movement of said fulcrum defining structure, said pivotal movement being in a direction tending to change the force condition on said spring in the sense opposite to the change due to movement of said fulcrum-defining structure thereby to provide a substantially constant support for the tare weight of the platform despite variation in the effective spring rate obtained by varying the rAtio of moment arms for said first and second loads.
 15. The self-leveling dispenser of claim 14 wherein said fulcrum is carried on a stationary track, and said track is angled to cause said change in force condition during the adjusting movement of said fulcrum along said track and beam.
 16. The self-leveling dispenser of claim 1 wherein said fulcrum-defining structure comprises a beam-engaging member carried by a link pivotally mounted on said frame, said fulcrum defined at the point of engagement between said beam and said beam-engaging member, and said adjusting means comprises an axially adjustable linkage connected to rotate said link thereby moving said beamengaging member along said beam to change the position of said fulcrum.
 17. The self-leveling dispenser of claim 16 wherein said beam has a curved surface where engaged by said beam-engaging member, the curvature of said surface being selected to maintain preselected tension conditions between said arm and said beam as said beam-engaging member travels over said curved surface in the arc defined by said pivotal link.
 18. The self-leveling dispenser of claim 17 wherein the curvature of said curved surface is selected to change the force condition on said spring in the sense opposite to the changes due to movement of said fulcrum to provide support for the tare weight of the platform despite variation in the effective spring rate obtained by varying the ratio of moment arms for said first and second loads.
 19. The self-leveling dispenser of claim 16 wherein a portion of said beam spaced from the area of said fulcrum means is pivotally connected to an elongated link, said elongated link extending generally in the same direction as said beam and pivotally mounted on said frame.
 20. A self-leveling dispenser comprising a frame, a platform supported for vertical movement, an elongated balance beam for balancing a first load and a second load applied to said beam at first and second load points, respectively, spaced along said beam on opposite sides of a fulcrum, a spring including first connecting means, said spring connecting at one end to said frame and at the other end to said beam at the first load point to provide said first load, second connecting means connecting said platform to said beam at the second load point to provide said second load, said connecting means constructed to apply their respective loads from substantially fixed positions relative to said frame, means defining a pivotal fulcrum for said beam, and means for adjusting the effective point of said fulcrum along the length of said beam and restraining means for generally restraining the beam against lengthwise movement during adjustment of the fulcrum, said restraining means comprising a freely pivotal elongated link mounted on said frame and secured to said beam at a linking point spaced substantially from said fulcrum, said elongated link extending from said linking point in the general direction of and past said fulcrum, said link positioning said beam longitudinally relative to said fixed positions.
 21. The self-leveling dispenser apparatus of claim 20 wherein the distance along said linking member between the pivotal mounting of said link on said frame and said linking point is greater than the distance along said beam between said load points.
 22. The dispenser of claim 20 wherein said linking point is coincident with one of said load points.
 23. The dispenser of claim 22 wherein said beam is coupled to the respective load at said coincident load point, by a sheave supporting an elongated flexible member connected to said load, the axis of said sheave being located at said coincident load point, said beam and said elongated links being connected at said linking point by a connecting pin coaxial with said sheave.
 24. The self-leveling dispenser of claim 23 wherein said elongated link traverses an arc less than about 30*.
 25. The dispensing apparatus of claim 20 whereIn said elongated link extends generally along the elongated axis of the mid position of said beam.
 26. A self-leveling dispenser comprising a frame, a generally vertically arranged elongated balance beam for balancing a first load and a second load applied to said beam at first and second load points, respectively, spaced along said beam, fulcrum means engaging said beam intermediate of said load points defining a fulcrum for said beam, a spring effectively connected at one end to said frame and at the other end to said beam to provide said first load, a vertically movable platform providing said second load, and platform support means comprising a first elongated flexible element engaged with one end of said beam at said second load point, guide means including a guide member for said flexible element mounted near the bottom of said frame, tie means connecting said elongated member at a point past said guide member to a cluster of at least three vertically oriented parallel elongated flexible members, separator means mounted on said frame near the top of said frame for receiving said cluster of parallel elongated members from said tie means and directing said members individually to selected spaced locations on said platform, and means securing said members to said platform at said spaced locations.
 27. The self-leveling dispenser of claim 26 including a multiple pulley arrangement having a mechanical advantage greater than two secured to said beam at said second load point, said first elongated flexible element passing around said pulley arrangement between said second load point and said guide member.
 28. The dispenser of claim 26 wherein said cluster of elongated elements are flexible cables, and said separator means comprises a plurality of sheaves mounted close to one another with their axes lying in a common plane.
 29. The self-leveling dispenser of claim 28 wherein there are three cables in said cluster, and said spaced locations on said platform are located near the two opposite corners of one side of said platform, and near the center of the opposite side of said platform.
 30. A self-leveling dispenser comprising a frame a platform supported for vertical movement a generally vertically arranged elongated balance beam for balancing a first load and a second load applied to said beam at first and second load points, respectively, on said beam fulcrum means engaging said beam at a third point intermediate of the load points defining a fulcrum for said beam, a spring connected at one end to said frame and at the other end to said beam at the first load point to provide said first load, means connecting said platform to said beam at the second load point to provide said second load, and adjusting means for varying the ratio of the first moment arm of said beam defined between said fulcrum and said first load point to the second moment arm of said beam defined between said fulcrum and said second load point, said adjusting means comprising an axially adjustable elongated linkage external of said beam, said linkage having a line of action disposed generally along the length of said beam, one end of said linkage terminating at a permanently positioned rotary knob mounted in an upper portion of the frame and accessible for rotation by an operator, the other end being arranged to move along said beam to alter the position of one of said three points along said beam to vary said ratio.
 31. The self-leveling dispenser of claim 30 wherein the movable end of said axially adjustable linkage is connected to move the point of action of said fulcrum means, and said adjustable linkage is stationary during vertical movement of the platform.
 32. The self-leveling dispenser of claim 31 wherein said fulcrum means comprises a beam-engaging member carried by a link pivoted to said frame, said movable end of said adjustable linkage connected to move said link to a preselected position, said beam being cOnstrained whereby the point of action of said fulcrum means is adjusted along said beam by said movement of said link.
 33. The self-leveling dispenser of claim 32 wherein a portion of said beam spaced from the area of said fulcrum means is pivotally connected to an elongated link, said link extending generally parallel to said beam and pivotally mounted on said frame.
 34. The self-leveling dispenser of claim 31 wherein said fulcrum means comprises a beam-engaging member carried along stationary guides.
 35. The self-leveling dispenser of claim 31 wherein said adjustable linkage comprises a pair of telescoping shafts threaded to each other, the upper shaft of said pair connected through a universal joint to said knob, the lower end of said pair connected to move said fulcrum means upon rotation of said knob.
 36. The self-leveling dispenser of claim 30 wherein said first load point for said spring is at the lower end of said moment arm and said adjustable linkage is longer than said moment arm, extending from the top of said dispenser downwardly to the lower end of said beam, said linkage adapted to shift said first load point along the length of said beam.
 37. The self-leveling dispenser of claim 30 wherein said adjustable linkage is adapted to move either said first or second load point along said beam, said linkage comprising a pivotal assembly including an axial lost motion connection permitting axial lengthening and shortening of said linkage during normal rotation of said beam during dispensing, said lost motion connection permitting free movement of said beam without affect upon the setting of said adjustable linkage.
 38. The self-leveling dispenser of claim 37 wherein said linkage comprises a pair of shafts telescopically fitted together and freely movable axially relative to each other to define said lost motion connection, said shafts being connected together for mutual rotation, the upper shaft of said pair connected through a universal joint to said rotatable knob, the lower shaft connected through a universal joint to a threaded lead screw mounted on said beam, and a nut constrained in guides of said beam, said nut providing the connection for said load, the nut being threaded on said screw and driven therealong by rotation of said screw. 